The subject matter disclosed herein relates generally to medical imaging systems, and more particularly to identifying and correcting charge-sharing events.
In nuclear medicine (NM) imaging, such as single photon emission computed tomography (SPECT) or positron emission tomography (PET) imaging, radiopharmaceuticals are administered internally to a patient. Detectors (e.g., gamma cameras), typically installed on a gantry, capture the radiation emitted by the radiopharmaceuticals and this information is used, by a computer, to form images. The NM images primarily show physiological function of, for example, the patient or a portion of the patient being imaged.
The detectors may include an array of pixelated anodes. If radiation emitted due to the radiopharmaceuticals is absorbed by the detector at a position resulting in sharing of the detected resulted charge between adjacent pixels, a shared charge event may occur. Shared charge events may not be large enough on either of the adjacent pixelated anodes to be recognized as an event to be counted, resulting in lost information and under counting. Certain known approaches for recovering or correcting charge-sharing events employ a concept of combining information from two adjacent pixels sharing a shared charge event. However, such approaches may have a number of drawbacks. For example, if one of a pair of events is below a threshold, the event may not be detected. As another example, a signal recovered from two pixels may be subject to additional noise (e.g., noise from two pixels instead of one), which may reduce a signal to noise ratio. Use of information from two pixels requires time-coincidence detection, addition computational or processing complexity. Further, use of information from two pixels may result in surface-recombination loss and/or may suffer from random coincidence of signals in adjacent pixels being mis-interpreted as a shared charge event.